Effect of arsenic trioxide on the treatment of children with newly diagnosed acute promyelocytic leukemia in China

To explore the efficacy of treatment for childhood acute promyelocytic leukemia (APL) with a combination of all-trans-retinoic acid (ATRA) and arsenic trioxide (As₂O₃) for remission induction, we reviewed the clinical course and outcome of 37 children with APL from January 1999 to December 2003. Among the 37 children (≤14 years) with newly diagnosed APL, we applied treatments that consisted of ATRA alone or in combination with As₂O₃ in induction followed by consolidation and maintenance treatment. Overall, 35 (94.6%) of 37 children achieved complete remission (CR). Two patients died of intracerebral hemorrhage on days 1 and 2. The 5-year estimates of event-free survival (EFS), disease-free survival (DFS), and overall survival (OS) rates for the 37 patients were 79.2, 83.7, and 91.5%, respectively. There were 27 patients with white blood cell (WBC) count lower than 10 × 10⁹/L. In 27 patients with a WBC count <10 × 10⁹/L, 17 patients (group-I) were treated with ATRA alone and 10 patients (group-II) were treated with ATRA which was switched to As₂O₃ due to the side effects of ATRA. Although the 5-year estimate of DFS between group-I and group-II showed no significant difference (P = 0.108), the DFS rate improved by 25% in group-II. Our results suggest that the combination of As₂O₃ and ATRA might decrease the relapse rate compared with ATRA alone in induction therapy for childhood APL, at least in those with a WBC count less than 10 × 10⁹/L.